## 4.3 Homework

(Polar molecules, Non-polar molecules, etc.)

Bree Perkins 1E
Posts: 34
Joined: Fri Apr 06, 2018 11:04 am

### 4.3 Homework

Hi Everyone,

I am confused on problem 4.3. How can part a) HCN be linear. Wouldn't the lone pair on N cause it to not be linear?

Also, how do you know that $CH_{2}N_{2}$ is tetrahedral rather than trigonal planar?

KristinaNguyen_1A
Posts: 30
Joined: Fri Apr 06, 2018 11:04 am

### Re: 4.3 Homework

HCN is linear because C will be the central atom, single bonded to H and triple bonded to N, with N have a lone pair of electrons but, I think, because the lone pair is on the N and not the central atom it will not cause the bonds to be pushed and so it remains as a linear.

CH2N2 is a tetrahedral and not trigonal planar because there are no lone pairs on central atom C and C is bonded with 4 elements= Tetrahedral. It would only be a trigonal planar if its central atom is only bonded to 3 other atoms, AX3.

Harmonie Ahuna-1C
Posts: 30
Joined: Fri Apr 06, 2018 11:01 am

### Re: 4.3 Homework

HCN is linear because lone pairs only affect shape when they're on the central atom- so only if they were on carbon would we see a different shape. For CH2N2, C is the central atom paired with all 4 atoms, making it tetrahedral.

Celeste Martinez 1K
Posts: 31
Joined: Fri Apr 06, 2018 11:04 am
Been upvoted: 1 time

### Re: 4.3 Homework

Since the lone pair is on nitrogen and not the central atom (carbon), then the shape is linear for HCN. CH2N2 is tetrahedral because carbon (center atom) is bonded with 4 atoms. If it was trigonal planar, carbon would've been bonded with three atoms.